System and method for managing location services in wireless networks

ABSTRACT

Described herein are methods, systems, apparatuses and products for managing location services in wireless networks. One aspect provides for broadcasting an identifier from a terrestrial wireless device in a determinable position; repeatedly changing the identifier broadcast from the terrestrial wireless device; and associating a current identifier broadcast from the terrestrial wireless device with a physical location. Other embodiments are disclosed.

FIELD OF THE INVENTION

The subject matter described herein generally relates to managinglocation services offered within a network. Certain aspects focus onmaintaining privacy.

BACKGROUND

In addition to offering technological advantages, femtocell deploymentsallow for precise fine-grained localization of mobile devices. Withfemtocell aided localization, as each femtocell base station's coveragearea is small, it becomes possible to determine whether a device isinside a house, at a particular restaurant, near a specific parkattraction, in a particular section of a store, or in a particular partof an office building. Femtocell-aided localization may become thepreferred method of localizing devices in indoor environments given thechallenge of using GPS receivers indoors. Additionally, femtocell-basedlocalization may be preferable over localization based on IEEE 802.11Wi-Fi hotspots since, while Wi-Fi is often turned off when not in use,cellular devices typically remain connected with the network at alltimes to be able to receive voice calls. Precise localization of mobiledevices offers many exciting opportunities, for example in entertainmenttheme parks, where users will not only be able to determine theirlocation on a map, but will also be able to interact with entertainmentattractions (for example, play scavenger hunt games, unlock treasures,et cetera).

Third-party localization systems (TLSs) that map wireless stationlocations and use the information later to provide devices withestimates of their positions are becoming more and more common. TLSs areable to localize mobile devices due to wireless stations broadcastingtheir unique and persistent station identifiers.

BRIEF SUMMARY

In summary, one aspect provides a method comprising: broadcasting anidentifier from a terrestrial wireless device in a determinableposition; repeatedly changing the identifier broadcast from theterrestrial wireless device; and associating a current identifierbroadcast from the terrestrial wireless device with a physical location.

Another aspect provides a method comprising: receiving a currentidentifier broadcast from a terrestrial wireless device in adeterminable position, wherein the terrestrial wireless devicerepeatedly changes an identifier that is broadcast; and using thecurrent identifier broadcast from the terrestrial wireless device todetermine a physical location associated with the terrestrial wirelessdevice.

Another aspect provides a method comprising: broadcasting a geocode asan identifier from a terrestrial wireless device, wherein the geocodecomprises an indicia of geographical location of the terrestrialwireless device.

Another aspect provides a method comprising: receiving in a mobiledevice an identifier broadcast from a terrestrial wireless devicelocated at a particular position; and using the identifier broadcastfrom the terrestrial wireless device to determine a physical location ofthe mobile device even in absence of a logical connection existingbetween the mobile device and the terrestrial wireless device.

The foregoing is a summary and thus may contain simplifications,generalizations, and omissions of detail; consequently, those skilled inthe art will appreciate that the summary is illustrative only and is notintended to be in any way limiting.

For a better understanding of the embodiments, together with other andfurther features and advantages thereof, reference is made to thefollowing description, taken in conjunction with the accompanyingdrawings. The scope of the invention will be pointed out in the appendedclaims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 illustrates an example station identity management system.

FIG. 2A illustrates handoffs due to W-ID change rate and device mobilityfor two representative values of device mobility.

FIG. 2B illustrates representative expected fractions of time thatstations will not have calls in progress for two representative callrates.

FIG. 3(A-B) illustrates probabilities of collision during a given timeinterval for different wireless technologies.

FIG. 4A illustrates a percentage of devices obtaining wrong coordinatesfrom a TLS database as a function of change rate.

FIG. 4B illustrates a percentage of devices obtaining wrong coordinatesfrom a TLS database for different change rates for given measurementsrequired to update the TLS database.

FIG. 5 illustrates an example multiple resolution location generation.

FIG. 6 illustrates an example of mobile devices using broadcastinformation to localize themselves at different resolutions.

FIG. 7 illustrates an example of determining location of a station thatis repeatedly changing identifiers.

FIG. 8 illustrates an example computer system.

DETAILED DESCRIPTION

It will be readily understood that the components of the embodiments, asgenerally described and illustrated in the figures herein, may bearranged and designed in a wide variety of different configurations inaddition to the described example embodiments. Thus, the following moredetailed description of the example embodiments, as represented in thefigures, is not intended to limit the scope of the claims, but is merelyrepresentative of those embodiments.

Reference throughout this specification to “embodiment(s)” (or the like)means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least oneembodiment. Thus, appearances of the phrases “according to embodiments”or “an embodiment” (or the like) in various places throughout thisspecification are not necessarily all referring to the same embodiment.

Furthermore, the described features, structures, or characteristics maybe combined in any suitable manner in different embodiments. In thefollowing description, numerous specific details are provided to give athorough understanding of example embodiments. One skilled in therelevant art will recognize, however, that aspects can be practicedwithout certain specific details, or with other methods, components,materials, et cetera. In other instances, well-known structures,materials, or operations are not shown or described in detail to avoidobfuscation.

Providing localization services for mobile devices having a staticidentifier is a well-developed research area and thus will not berecounted extensively here. However, to provide context, manylocalization services (referred to herein as Third Party LocalizationServices, TLS(s)) operate essentially as follows. First, a devicecapable of localizing itself (for example, a GPS enabled device) surveysan area, recording station identifiers it overhears (referred to hereinas a wireless station ID, or W-ID), and then it estimates of thestations' locations. The location information captured by the device isrecorded in a centralized TLS database. Later, client devices that wantto localize themselves submit the W-IDs they overhear to the database,get back location information (the location(s)) of the correspondingbase stations, and localize themselves based on this data. This approachto localization works as long as unique and persistent station W-IDs aretransmitted by base stations (femtocell base stations, cell towers,Wi-Fi hotspots, et cetera).

Thus, TLSs are able to localize mobile devices due to wireless stationsbroadcasting their unique and persistent station identifiers. However,such localization services may introduce privacy concerns. For example,severe security and privacy risks exist when unauthorized third partiesare allowed to localize devices at a level of precision made possible byfemtocell deployments. For example, allowing third-party systems toprecisely determine where devices are in an office may lead to leakageof important business information. Moreover, wireless base stationsbroadcasting their unique and persistent station identifiers allowsthird party location services to provide location services withoutproviding compensation.

Conventional interest in preserving location privacy focuses on locationprivacy of mobile devices themselves, rather than on base stations'location privacy. Additional related research includes examinations ofTLS compromises and security considerations for device-to-TLS-databasecommunications. However, these do not address preservation of a basestation's location privacy.

Accordingly, an embodiment preserves location privacy of wireless basestations. An example embodiment, referred to herein as an IntelligentStation Identity Manager (ISIM) system, preserves location privacy ofwireless base stations by making their identities (W-IDs) dynamic. InISIM, globally unique station identities are not shared with mobiledevices or third-party systems. Instead, the wirelessly broadcaststation identities that are shared are dynamic, and are repeatedlychanged, for example based on some policy, such as a policy determinedby a femtocell network operator.

In conjunction with the preservation of location privacy, an embodimentprovides authorized systems with location information, which may be ofdifferent resolution level. An example embodiment, which includes amodule referred to herein as a Multiple Resolution Location Generator(MultResLoc) module, provides location information at a resolution thatmay depend on permission level(s) granted, for example by the networkoperator. For example, the permission level could depend on the level ofservice a system purchased, or the type of user/client device requestinglocation services, or the like. For example, different levels oflocalization information (different resolutions) may be provided tousers with dedicated client devices and users with general-purpose smartphones or laptops, and/or different levels of localization informationmay be provided to users based on the application that requests thelocalization information, and the like.

It is contemplated that in some embodiments the W-ID may be configuredto include location information such as a geocode where the locationinformation comprises explicit (i.e., literal) or implicit (i.e., mappedor abstracted) indicia of the physical location of the transmitting basestation (e.g., a latitude, longitude, and/or altitude). In embodimentswhere location privacy is not a concern, this feature can allow a mobiledevice to use the location information by simply listening to the W-IDwithout need to connect to the transmitting base station or access athird party localization service. In a specific example, latitude andlongitude are placed literally within the thirty-two character SSID of aWiFi access point such that any passing WiFi enabled mobile device candetermine the location information without connecting to the accesspoint. In embodiments where location privacy is a concern, the locationinformation can be encrypted with a static key or a repeatedly changingkey to achieve privacy benefits similar to dynamic W-ID's describedherein. In these embodiments mobile devices may be modified to includesoftware capable of determining the location information from the W-IDand supplying that determined location information to other softwareprocesses in the mobile device that can make further use of the locationinformation.

Furthermore, an embodiment provides a system to determine base stationlocations even if dynamic W-ID changing is employed by the stations. Anexample embodiment provides a monitoring device of know location thatmay be situated near a broadcasting base station such that the dynamicW-IDs may be associated with a known location, that is, the location ofthe monitoring device. The monitoring device may provide dynamic updatesto a location database at an appropriate rate given the W-ID change rateof the base station in question.

It should be noted that example embodiments are described herein with afocus on 3GPP Long Term Evolution (LTE) and WiMAX IEEE 802.16femtocells. However, these are merely used as representative examples toprovide clear and precise description. Those having ordinary skill inthe art will recognize that the developed approaches described inconnection with the example embodiments may be applied to otherfemtocell technologies (such as, CDMA2000 or TD-SCDMA femtocells), aswell as to Wi-Fi IEEE 802.11 hotspots, other base stations, and thelike. For example, the stations, base stations, and/or femtocell basestations referred to herein include more generally any terrestrialwireless device having a (at least temporarily) fixed position,including but not limited to wireless base stations, wireless accesspoints, femtocells, short-range wireless devices/BLUETOOTH devices, andthe like, as compared with satellites (non-terrestrial wireless devices)used for GPS.

Similarly, the identifiers referred to herein for such terrestrialwireless devices may vary according to the particular technology, butmay include for example a cell phone base station identifier; a Wi-Fidevice identifier; a short range wireless technology device/BLUETOOTHdevice identifier; and a Worldwide Interoperability for Microwave Access(WiMAX) device identifier, and the like. Thus, depending upon theparticular device(s) and technologies used, the identifier that isbroadcast may include for example a service set identification (SSID), aMAC address, an IP address, and the like.

Moreover, the devices consuming the location information describedthroughout as user devices, client devices, and the like should beunderstood to generally include mobile client devices, for example smartphones, lap top computers, dedicated mobile computing devices, mobilecomputing devices generally, and the like; or, as further describedherein, a monitoring device.

The description now turns to the figures. The illustrated exampleembodiments will be best understood by reference to the figures. Thedescription is intended only by way of example and simply illustratescertain example embodiments representative of the invention, as claimed.

Intelligent Station Identity Management

According to an embodiment, an Intelligent Station Identity Manager(ISIM) module 101 preserves base stations' location privacy by makingwirelessly transmitted station identities (W-IDs) dynamic. Somenomenclature used throughout is summarized in Table I as a quickreference.

TABLE 1 Nomenclature f*_(j) Permanent station ID of femtocell basestation j WID(f*_(j), T_(i)) Dynamic station ID of base station j attime T_(i) k Number of bits in the W-ID that are modified x Size of theW-ID space λ_(ch) Rate of W-ID changes [1/h] t_(ch) Time a W-ID changetakes [s] N_(nbr) Number of stations in a neighborhood L Number ofstations synchronously changing W-IDs K Number of calls a station cansimultaneously maintain λ_(call) Femtocell base station call arrivalrate [1/h] h_(call) Average call duration [h] a Femtocell coverage area[m²] d Distance a mobile device travels inside a femtocell [m] v Averagemobile device speed [m/s] c_(dev) Concentration of mobile devices [1/m²]f_(loc) Fraction of devices reporting locations to a TLS F Total numberof base stations running ISIM

An example system structure is shown schematically in FIG. 1. Eachfemtocell/base station 110, j, (only one is illustrated for simplicity)has a unique ID, f*_(j). The f*_(j) is used in the femtocell's (j) 110communication with the rest of the cellular network 120 (macrocell,gateways, et cetera). However, f*_(j) is not revealed (broadcast) to themobile devices 130 accessing the femtocell base station 110. For each j110, the wirelessly broadcast identity (femtocell W-ID) is a dynamic,time-dependent entity that is repeatedly changed, termed herein as: W-ID(f*_(j), T_(i)), where T_(i) denotes the time instance. Note that anembodiment provides that the station ID visible to the rest of thenetwork 120, f*_(j), does not change with time. Thus, an embodiment doesnot require modifications to the overall network architecture. Forexample, cellular operator-side services, such as E911 and E112services, are not affected.

The dynamically generated W-IDs may follow the femtocell technology(LTE, WiMAX, et cetera) specifications. In the representative exampletechnologies described in detail herein, the wirelessly broadcastinformation that identifies a station 110 is as follows:

W-CDMA/LTE: each base station 110 has a globally unique Cell GlobalIdentity (CGI). A CGI consists of a set of codes identifying the networkarea, and also includes a 16 bit long Cell Identity code that can bemodified. The standards also define an optional femtocell HNB Name,which is a maximum of 48 characters long. In addition, in LTE, the cellcan be identified by a locally unique Physical Cell Identity (PCI). LTEallows for only 504 PCIs.

IEEE 802.16 (WiMAX): each base station 110 has a 48 bit long basestation ID (BSID), where 24 bits indicate the station operator and theremaining 24 bits can be modified.

Accordingly, if the number of W-ID bits that may be altered is denotedby k, and the size of the W-ID selection space is denoted by x, wherex=2^(k), in cellular systems x is upper-bounded by 2¹⁶, and in WiMAX themaximal x is 2²⁴. Again, these are merely used as representativeexamples.

W-ID changes may be performed by ISIM module 101 with a target nominalchangeover rate, termed herein as λ_(ch). When a femtocell base station110 changes its W-ID, it disconnects its mobile clients 130 and becomestemporarily unavailable. This may impact the performance of thefemtocell base station 110, as described further herein.

To facilitate description of potential impact on femtocell base stationperformance, some nomenclature used throughout is first set forth. Thetime it takes a femtocell station 110 to complete a W-ID change isdenoted by t_(ch). The number of stations in a neighborhood (again, onlyone station is shown in FIG. 1 for simplicity) is denoted by N_(nbr),and L is used to denote the number of stations simultaneously changingtheir W-IDs. A W-ID change can be initiated by a station 110 itself, orby a controller with a more global knowledge. The number of calls astation 110 can simultaneously maintain is denoted by K, the averagecall duration is denoted by h_(call), and the call arrival rate isdenoted by λ_(call). The area covered by a femtocell 110 is denoted bya, and the average distance a device (for example, one of devices 130)moves inside a femtocell coverage area is denoted by d. Additionally, vand c_(dev) denote, respectively, the speed and the concentration ofmobile devices 130. For example, in numerical results, d=10 m (for anexample small femtocell), a=d·d=100 m², and v=1.5 km/h (which representsvery slow walking).

It is expected that femtocell stations (for example 110) may beassociated with many devices 130, but also be relatively lightly loadedwith traffic. This is a reasonable assumption for many publicenvironments, such as stadiums or entertainment parks.

Effect on Femtocell System Performance

In general, femtocell base stations (for example 110) performing W-IDchanges may affect system performance. It should be noted, however, thatW-ID changes only affect the femtocell stations' wireless interface.During W-ID changes, mobile clients 130 can connect to a macrocell whosefunctionality is not affected. The femtocell base station 110 connectionwith the rest of the cellular operator network 120 is also not affected.

The number of calls not serviced due to a base station 110 changing itsW-ID is simply λ_(call)=t_(ch)·λ_(ch). This indicates that t_(ch) shouldbe kept short if relatively frequent W-ID changes are desired. For alightly loaded system (small λ_(call)), the femtocell base station's 110inaccessibility associated with W-ID changeovers should not besignificant, particularly since the devices 130 are serviced by amacrocell while the femtocell 110 is temporarily inaccessible.

When a femtocell base station 110 performs a W-ID change, the devices130 within its coverage area that have calls in progress have tohandoff. In many practical environments, however, the number of handoffsdue to mobility is substantially higher than the number of handoffsintroduced by W-ID changes. It can be demonstrated thatλ_(hoff,m)/λ_(hoff,e)=(v/d)/λ_(ch), where λ_(hoff,c) and λ_(hoff,m), arethe handoff rates due to W-ID changes and due to mobility, respectively.FIG. 2A shows the λ_(hoff,m)/λ_(hoff,e) ratio as a function of λ_(ch)for two different values of average mobile device speed v. It can beobserved from FIG. 2A that handoffs due to mobility greatly exceedhandoffs due to W-ID changes. Even for relatively frequent W-ID changes(10-12 times per hour), λ_(hoff,m) is over 10 times greater thanλ_(hoff,c).

W-ID changes should be conducted without disrupting calls in progress,if possible. λ_(ch) is the target W-ID change rate since the W-ID changeis not necessarily performed at the exact 1/λ_(ch) intervals; rather,the stations (for example, 110) may wait until they have no calls inprogress to change their W-IDs. The expected fraction of time that Lstations do not have calls in progress, f_(em) ^(L), can beapproximated, using M/M/K queue formulations, as

$f_{em}^{L} = {P_{0}^{tot} = {{{P_{0}(1)} \cdot \ldots \cdot {P_{0}(L)}} = \left( {\sum\limits_{n = 0}^{K}\;{\frac{1}{n!}\left( \frac{\lambda_{call}}{1\text{/}h_{call}} \right)}} \right)^{- L}}}$and is demonstrated in FIG. 2B as a function of the number of stations Lfor two different values of λ_(call). It can be observed from FIG. 2Bthat when L is relatively small, the expected fraction of time thestations (for example, 110 of FIG. 1) do not have calls in progress isrelatively high, and thus it should be generally possible to not disruptthe calls in progress to change the W-IDs.

W-ID Selection Schemes: Centralized and Distributed

For each time interval T_(i), W-ID (f*_(j), T_(i)) can be set by thestation j 110 itself, or by a control station (distributed orcentralized W-ID selection). A W-ID collision happens when more than onestation j 110 in a neighborhood uses the same WID (f*_(j), T_(i)) forthe same T_(i). Some of the station identities that may be modifiedaccording to an embodiment, such as GCIs and MAC addresses, areconsidered by the protocols to be fixed and unique, and collisionsbetween them are highly undesirable. For others, such as LTE PCIs,collision alleviation mechanisms exist, but nonetheless it may bepreferable to avoid collisions. Collisions are easily avoided with acentralized mechanism, but are possible with distributed assignments.

W-ID collision probability can be upper-bounded as follows. Suppose eachstation 110 sets its W-ID randomly. The probability of a W-ID collisionduring time interval T is denoted by P_(T):

${P_{T} = {1 - \left( {1 - p_{c}} \right)^{T \cdot \lambda_{ch}}}},{{{where}\mspace{14mu} p_{c}} = {1 - \left( \frac{x - 1}{x} \right)^{\frac{N_{nbr} \cdot {({N_{nbr} - 1})}}{2}}}}$As previously noted, the W-ID selection space x used in thesecalculations depends on the femtocell technology, and thus for differenttechnologies P_(T) differs drastically. For example, FIG. 3(A-B)demonstrates P_(T) as a function of λ_(ch) for two different values ofN_(nbr) for two different technologies. FIG. 3A demonstrates P_(T)values for IEEE 802.16 BSIDs (x=2²⁴) for T=year, while FIG. 3Bdemonstrates P_(T) for LTE PCI (x=504) for T=day. It can be observedfrom FIG. 3(A-B) that probabilities of W-ID collisions are high for LTEPCIs and low for IEEE 802.16 BSIDs. Thus, for IEEE 802.16, simpledecentralized BSID assignment schemes may be used, while for LTE,coordinated PCI assignments may be preferable.

Where decentralized assignments are suitable, stations (for example, 110of FIG. 1) may, for example, use cryptographic hash functions toindependently generate their W-IDs. Simple algorithmic improvements(that is, considering W-IDs of neighboring stations) may reduce thenumber of W-ID collisions relative to the above-stated upper bounds.More involved distributed assignment algorithms, such as those based ongraph coloring, could also be considered.

Effects on the Performance of Third-Party Localization Services (TLSs)

As described herein, it is common for TLSs to prepare a centralizeddatabase having W-ID-to-locations mappings, and look up the mappingswhen localizing a device (for example, one of client devices 130 inFIG. 1) based on the W-IDs it is overhearing. When dynamic W-IDs arereported to a TLS's centralized database, database integrity will becomedifficult to preserve. In-database W-ID collisions would be a majorissue for a centralized TLS database, such as when dynamic W-ID changingis employed. For the femtocell system, W-ID collisions are “local”, andtheir probabilities are relatively small due to a relatively smallnumber of neighboring stations N_(nbr). Using f_(loc) to denote thefraction of devices that update a TLS database with W-ID-to-locationmappings and F to denote the overall number of femtocell base stationsstored in a TLS database, these difficulties may be formulated asfollows.

When locations and W-IDs of F different femtocell stations (whereF>>N_(nbr)) are aggregated, the probability of a W-ID collision in aninterval T is

$P_{T} = {1 - \left( \frac{x - 1}{x} \right)^{\frac{T \cdot \lambda_{ch} \cdot {F{({{T \cdot \lambda_{ch} \cdot F} - 1})}}}{2}}}$which is generally high since the number of possibly colliding entries,T·λ_(ch)·F, is large. For example, for F=100 and λ_(ch)=4, P_(T)>99%when T is just an hour.

Typically, a TLS needs to obtain a number of W-ID-to-location reports(messages, measurements) from wireless devices before it updates itsdatabase with a W-ID-to-location mapping. For example, assume that a TLSupdates its database after a single device reports an updatedWID-to-location mapping. The time until the first such device arrives toa femtocell is denoted by T_(loc). It can be demonstrated that

(T_(loc))=[d/v]/[f_(loc)·c_(dev)·a]. Prior to T_(loc), all mobiledevices (such as one of client devices 130 in FIG. 1) that requestlocation information from a TLS receive grossly incorrect information(or no information at all). The number of these client devices (forexample, client devices 130) is 1/f_(loc), and their percentage (wrongcoordinates) is demonstrated in FIG. 4A for f_(loc)=1% for two differentvalues of client device (for example, client devices 130) concentrationc_(dev). It can be observed from FIG. 4A that a substantial percentageof client devices (for example, client devices 130) relying on a TLSobtain wrong location information (which is desired according to anembodiment) when the W-ID change is performed as infrequently as four tosix times per hour. The percentage of client devices (for example,client devices 130) receiving incorrect information, for a morepractical case of a TLS requiring more than one report (message,measurement) prior to updating its database, is demonstrated in FIG. 4B.It can be observed from FIG. 4B that the percentage of client devicesreceiving wrong information (coordinates) grows with the number ofmeasurements (messages) required by a TLS.

Multi-Resolution Location

As described herein, an embodiment prevents unauthorized parties fromobtaining base station location information via use of dynamic W-IDs. Anembodiment may also provide the location information selectively, forexample to authorized client devices, users, applications, and the like,via protecting the location information broadcast and/or protectingaccess to stored location information such that only authorizeddevices/applications/parties may obtain the location information. Thelocation information may be protected in a variety of ways, such asthrough various encryption schemes, requirements for credentials, andthe like.

An example embodiment provides selective location information via aMulti-Resolution Location Generator (MultResLoc) module 560, asillustrated in FIG. 5. Femtocell base station locations, such as that ofbase station 510, may broadcast wirelessly throughout the femtocell atmultiple resolution levels (for example, accurate to within 1 m,accurate to within 100 m, accurate to within 1000 m and the like), allat the same time, as shown schematically in FIG. 5. Each femtocell basestation 510 may specify its location with several levels of precision,and separately protect, for example via encryption, each of thespecified resolution levels. Conversely, instead of broadcasting thelocation information, access to stored location information may beprovided selectively using a protection scheme, such as encryption,requirement for credentials/authentication, and the like.

FIG. 6 demonstrates an example of how mobile client devices 630A, 630B,630C may use broadcast information to localize themselves. In theexample illustrated, each client device 630A, 630B, 630C decrypts thelocation information corresponding to its permission level. Thus, clientdevices 630A and 630C may be given a key that enables them to decryptencrypted location coordinates of 1000 m and 100 m resolutions,respectively. In contrast, client device 630B does not have (or haveaccess to) a key for any of the broadcast information, and thus cannotmake use of the broadcast location information. Similarly, retrieval oflocation information by client devices may be restricted, at differentresolution levels, based on another protection scheme, such as byrequiring a client device to authenticate itself using credentials priorto releasing location information, where the level of accuracy of thelocation information accessible by the client is dependent upon thecredentials supplied, et cetera. In one example, the locationinformation may be intentionally erroneous and/or random, such asresponsive to determining the credentials are received from a TLSdevice. This may be used to prohibit TLS devices from making use of oneor more base stations' location information. Such an approach mayinclude using planned error introduced into a neighborhood of basestations such that a TLS device may not determine the true locationsfrom listening to more than one base station.

The design parameters in MultResLoc 560 may include for example thenumber of supported resolutions and area specifications, which depend ontechnical parameters (for example, system complexity and base stationlocations), as well as business needs. Using MultResLoc 560 to providelocation information may be desirable when the previously described ISIMmodule 101 is used to preserve the location privacy of the femtocellbase stations 110. The combination of MultResLoc 560 and ISIM 110 givesoperators the full control to manage location privacy in cellularnetworks, such as networks with femtocell deployments.

Referring to FIG. 7, an embodiment provides a system to determine basestation locations even if dynamic W-ID changing is employed. Forexample, a monitoring device 740 (of know location) may be positionednear a femtocell base station 710. This monitoring device 740, which maybe stationary, is able to observe at all times the W-IDs the station 710uses. This information may be reported by the monitoring device 740 to adatabase 750. Given the current W-ID of the base station 710, and theknown location of the monitoring device 740 relative to the base station710, accurate positioning information may be delivered to mobile clientdevices 730, even if a base station 710 is dynamically changing W-IDs.This is in contrast to existing TLSs, in which the monitoring devicesare only suitable for collecting static W-IDs, as described herein.Thus, a site owner, for example in a stadium or a theme park, maybenefit from monitoring the changing station W-IDs implemented by acarrier by positioning monitoring nodes, such as monitoring device 740,next to the femtocell base stations, such as base station 710, locatedon the site.

Referring to FIG. 8, it will be readily understood that certainembodiments can be implemented using any of a wide variety of devices orcombinations of devices. An example device that may be used inimplementing embodiments includes a computing device in the form of acomputer 810. In this regard, the computer 810 may execute programinstructions configured to dynamically change W-IDs, and perform otherfunctionality of the embodiments, as described herein.

Components of computer 810 may include, but are not limited to, at leastone processing unit 820, a system memory 830, and a system bus 822 thatcouples various system components including the system memory 830 to theprocessing unit(s) 820. The computer 810 may include or have access to avariety of computer readable media. The system memory 830 may includecomputer readable storage media in the form of volatile and/ornonvolatile memory such as read only memory (ROM) and/or random accessmemory (RAM). By way of example, and not limitation, system memory 830may also include an operating system, application programs, otherprogram modules, and program data.

A user can interface with (for example, enter commands and information)the computer 810 through input devices 840. A monitor or other type ofdevice can also be connected to the system bus 822 via an interface,such as an output interface 850. In addition to a monitor, computers mayalso include other peripheral output devices. The computer 810 mayoperate in a networked or distributed environment using logicalconnections (network interface 860) to other remote computers ordatabases (remote device(s) 870). The logical connections may include anetwork, such local area network (LAN) or a wide area network (WAN), acellular network, but may also include other networks.

It should be noted as well that certain embodiments may be implementedas a system, method or computer program product. Accordingly, aspectsmay take the form of an entirely hardware embodiment, an entirelysoftware embodiment (including firmware, resident software, micro-code,et cetera) or an embodiment combining software and hardware aspects thatmay all generally be referred to herein as a “circuit,” “module” or“system.” Furthermore, aspects may take the form of a computer programproduct embodied in computer readable medium(s) having computer readableprogram code embodied therewith.

Any combination of computer readable medium(s) may be utilized. Thecomputer readable medium may be a non-signal computer readable medium,referred to herein as a computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer readable storage medium would include the following: anelectrical connection having at least one wire, a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), an optical fiber, a portable compact disc read-only memory(CD-ROM), an optical storage device, a magnetic storage device, or anysuitable combination of the foregoing.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, et cetera, or any suitablecombination of the foregoing.

Computer program code for carrying out operations for various aspectsmay be written in any programming language or combinations thereof,including an object oriented programming language such as Java™,Smalltalk, C++ or the like and conventional procedural programminglanguages, such as the “C” programming language or similar programminglanguages. The program code may execute entirely on a single computer(device), partly on a single computer, as a stand-alone softwarepackage, partly on single computer and partly on a remote computer orentirely on a remote computer or server. In the latter scenario, theremote computer may be connected to another computer through any type ofnetwork, including a local area network (LAN) or a wide area network(WAN), or the connection may be made for example through the Internetusing an Internet Service Provider.

Aspects have been described herein with reference to illustrations ofmethods, apparatuses, systems and computer program products according toexample embodiments. It will be understood that some or all of thefunctionality in the illustrations may be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a computer or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the illustrations.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the functions/acts specified in the illustrations.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer, or other programmable apparatus, provide processes forimplementing the functions/acts specified in the illustrations.

This disclosure has been presented for purposes of illustration anddescription but is not intended to be exhaustive or limiting. Manymodifications and variations will be apparent to those of ordinary skillin the art. The example embodiments were chosen and described in orderto explain principles and practical application, and to enable others ofordinary skill in the art to understand the disclosure for variousembodiments with various modifications as are suited to the particularuse contemplated.

Although illustrated example embodiments have been described herein withreference to the accompanying drawings, it is to be understood thatembodiments are not limited to those precise example embodiments, andthat various other changes and modifications may be affected therein byone skilled in the art without departing from the scope or spirit of thedisclosure.

What is claimed is:
 1. A method comprising: receiving a currentidentifier broadcast from a terrestrial wireless device in adeterminable position, wherein the terrestrial wireless devicerepeatedly changes an identifier that is broadcast; using the currentidentifier broadcast from the terrestrial wireless device to determine aphysical location associated with the terrestrial wireless device; andplacing a monitoring device within wireless transmission range of theterrestrial wireless device; wherein said receiving step is performed bythe monitoring device.
 2. The method according to claim 1, wherein thecurrent identifier broadcast from the terrestrial wireless devicecomprises one or more of: a cell phone base station identifier; awireless access point device identifier; and a short range wirelesstechnology device identifier.
 3. The method according to claim 1,wherein the current identifier broadcast from the terrestrial wirelessdevice comprises one or more of a service set identification, a MACaddress, and an IP address.
 4. The method according to claim 1, whereinthe terrestrial wireless device comprises one or more of a cellular basestation, a femtocell base station, and a wireless access point device.5. The method according to claim 1, wherein said receiving over anetwork a current identifier broadcast from a terrestrial wirelessdevice is performed by a client device.
 6. The method according to claim5, wherein the client device comprises one or more of a mobile phone anda mobile computing device.
 7. The method according to claim 1, furthercomprising: maintaining in a database an association of the currentidentifier broadcast from the terrestrial wireless device and thephysical location.
 8. The method according to claim 7, furthercomprising: consulting the database to look up the association of thecurrent identifier broadcast from the terrestrial wireless device withthe physical location.
 9. The method according to claim 1, furthercomprising: receiving location information at a client device.
 10. Themethod according to claim 9, wherein accuracy of the locationinformation depends upon an access level of the client device.
 11. Themethod according to claim 9, further comprising: providing credentialsto a remote device; and receiving location information whose accuracydepends upon the credentials supplied.
 12. The method of claim 1,wherein the current identifier broadcast from the terrestrial wirelessdevice is protected.
 13. The method according to claim 12, wherein alevel of protection for the current identifier broadcast from theterrestrial wireless device modulates accuracy of location informationof the physical location.
 14. The method of claim 12, wherein thecurrent identifier broadcast from the terrestrial device is encrypted.